Let’s rephrase that: “If you look at traditional diets in their non-adulterated form, they are, by and large, healthy,” says Dr. Daphne Miller, the author of Farmacology and The Jungle Effect as well as an expert on food around the world.

She’s found that time-honored, unprocessed eating patterns are generally much better for you than modern, Westernized ones, which are full of fat, sugar and additives.

Of course, it’s not all about the food; it’s how you consume it. Our mealtime habits (pace, portion size, etc.) affect our bodies, as do exercise, genetics and culture. We took these factors into account when compiling its list of the world’s healthiest and unhealthiest regional diets, and came up with the following:

GOOD: Japan and South Korea

“What all traditional diets have in common is balance, variety depending on the season, and moderate portion size,” says Miller. No one demonstrates those principles better than the Japanese, whose reliance on seasonal produce, soy, rice and fish translates to rock-bottom diabetes and obesity rates, as well as the third-longest life expectancy in the world (behind only Monaco and Macau).

Just across the Sea of Japan lies South Korea, whose cuisine is influenced by the Chinese and Japanese. It also incorporates lots of vegetables and seafood — “Coastal areas rely more on fish for protein,” says Miller — in addition to sensible quantities of beef and noodles. As a result, the incidence of cardiovascular disease is among the lowest on Earth.

Here’s a startling statistic: In some Polynesian countries, more than 90 percent of the adult population is overweight. According to the CIA, the tiny island nations off Australia claim the Top 10 diabetes rates in the world, not to mention nine of the Top 10 obesity rates.

Much of the problem stems from dietary changes. “Polynesian food traditionally was a lot of fish, greens and root veggies, and pork on special occasions,” says Miller. But these days, imported, processed foods — especially canned meats — have largely replaced traditional dishes, causing cardiovascular diseases to skyrocket. Local initiatives are confronting the issues head-on, but it’s an uphill battle.

Scandinavians know healthy eating. Sticking close to traditional diets with lots of grains, fruit and seafood, their obesity rates rank near the bottom of developed countries. Vegetables play large roles, too, but their availability is determined largely by the region’s frigid climate; vitamin-packed root veggies like potatoes and turnips are more common than leafy greens.

Of course, the Nordic diet doesn’t lack for rich food — bread, dairy, and meat are prevalent — so how do Scandinavians avoid related health issues? The answer: small portions of excellent chow. “Meat or dairy is eaten more in some zones,” says Miller. “But it is always meat that has eaten well itself and therefore passes on its nutrients to the consumer.”

BAD: Arabian Peninsula

Its countries include Saudi Arabia, Kuwait, Bahrain, United Arab Emirates, Jordan and Qatar.

Much like Polynesia, oil-rich Middle Eastern nations have largely pushed healthy traditional diets (lean meats, grains, fruit, etc.) aside for modern conveniences. The results are just as harmful: steep rises in obesity, cardiovascular problems and diabetes, plus lower life expectancies. In fact, Oxfam, the British-based advocacy group, ranked Saudis as the world’s unhealthiest eaters in a 2014 report.

The reasons? Well, fast food is one key culprit, as many Arabs have embraced food halls and chains like McDonald’s and Pizza Hut. Westernized grocery stores and imported products, which typically contain more fats and sugars than locally grown foods, are also big-time factors.

One reason it’s so successful: Followers shun modern processed foods for simple, time-honored fare. “Most traditional diets use legumes and root vegetables, [beans], and greens as the basis of their diet,” says Miller. For Greece and its neighbors, that means olive oil, leafy greens, fruit, beans, whole grains and fish along with judicious servings of dairy, meat and antioxidant-rich red wine. Not a bad menu, eh?

For centuries, traditional Mexican diets balanced waist-widening goodies like enchiladas with grains, beans, vegetables, fruits and spices. As a result, illnesses like diabetes were practically non-existent.

Today, things are different. The 1970s and 80s saw a flood of processed foods and beverages south of the border, leading to unprecedented spikes in obesity, diabetes and cardiovascular disease. Soda is a particular issue, as Mexicans consume more of it than anyone else in the world. The problem is so bad, the government has begun taxing junk foods.

BAD: United States

You knew that Americans have a famously unhealthy diet, with too much “sodium, saturated and trans fats, added sugars and refined grains,” according to the USDA. But did you know it caused this many problems?:

About two-thirds of the population is overweight. Half of those people are obese.

Recent reports show that national obesity rates have stabilized, and are dropping among young children.

This means, with notable exceptions, most Americans have the ability to eat well (and many do). The USDA and initiatives like Michelle Obama’s Let’s Move! are working to ensure that becomes the norm, especially for children.